Angled ductwork fittings, flexible fitting machine and methods of manufacture

ABSTRACT

Machines and methods for making an angled ductwork fitting from a length of flexible spiral pipe, which may be flat oval, having two ends. A pair of end securing devices are attachable to respective ends of the length of flexible spiral metal pipe. A mechanism moves the end securing devices relative to each other through a range of movement to an end position which effects bending of the length of spiral metal pipe to a desired angled configuration. Another disclosed method employs a preformed inflatable bladder which, when inflated, assumes the shape of an elbow. The preformed inflatable bladder is inserted in collapsed form into a length of flexible spiral metal pipe, and thereafter inflated.

CROSS-REFERENCE TO PROVISIONAL PATENT APPLICATION

[0001] The benefit of U.S. provisional patent application Ser. No. 60/169,076, filed Dec. 6, 1999, is claimed.

BACKGROUND OF THE INVENTION

[0002] The invention relates to angled ductwork fittings, such as elbows and offsets, used for joining sections of round spiral and flat oval ductwork, such as is employed in heating, ventilation and air conditioning (HVAC) system applications.

[0003] Conventional practice is to employ die-formed elbows and gored elbows. Both die-formed elbows and gored elbows are available from E. H. Gustafson & Co., 5115 Suffield Terrace, Skokie, Ill. 60077. Die-formed and gored elbows are conventionally available in increments of 30°, 45°, 60° and 90°.

[0004] With reference to FIGS. 1 and 2, a prior art gored elbow 10 joins two flat oval ductwork sections 12 and 14. The ductwork sections 12 and 14 however are representative of a variety of elements which it may be desired to join at right angles, such as transition fittings or air distribution louvers.

[0005] Gored elbows are hand-manufactured by cutting triangular sections out of round pipe, bending and welding. The particular gored elbow 10 of FIGS. 1 and 2 is a 90° elbow, and comprises a set of five sections 16, 18, 20, 22 and 24, called gores, that are individually cut out, rolled, fastened and fitted together. A substantial amount of time is required to produce a gored elbow, and they are relatively costly.

[0006] Thus, conventional fittings are manufactured either in several pieces as gores that are welded or mechanically joined, or by stamping the fitting from a solid piece of metal. The stamped fittings are limited in size to approximately fourteen inches in diameter.

SUMMARY OF THE INVENTION

[0007] The invention is embodied in a machine for making an angled ductwork fitting from a length of flexible spiral metal pipe having two ends. The length of flexible spiral metal pipe may be flat oval. The machine includes a pair of end securing devices attachable to respective ends of the length of flexible spiral metal pipe, as well as a mechanism for moving the end securing devices relative to each other, while attached to the respective ends, through a range of movement to an end position which effects bending of the length of the spiral metal pipe to a desired angled configuration.

[0008] A method embodying the invention includes the steps of providing a length of flexible spiral metal pipe having two ends, and employing the machine to manipulate the length of flexible spiral metal pipe to a desired configuration.

[0009] Another method embodying the invention includes the steps of providing a length of flexible spiral metal pipe having two ends, and providing a preformed inflatable bladder which, when inflated, assumes the shape of an elbow. The preformed inflatable bladder is inserted in a collapsed form into the length of flexible spiral metal pipe, and thereafter inflated.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010]FIG. 1, referred to hereinabove, depicts a prior art gored elbow;

[0011]FIG. 2, also referred to hereinabove, is a cross-section taken on line 2-2 of the prior art gored elbow;

[0012]FIG. 3 is a three-dimensional representation of a first machine embodying the invention;

[0013]FIG. 4 is a three-dimensional representation similar to FIG. 3, depicting additional elements of the first machine embodying the invention;

[0014]FIG. 5 is a side elevational view of a second representative machine embodying the invention;

[0015]FIG. 6 is a plan view depicting a third representative machine embodying the invention, prior to movement to effect bending of a length of spiral metal pipe;

[0016]FIG. 7 is a plan view of the machine of FIG. 6, subsequent to movement to an end position which effects bending of the length of spiral metal pipe to a desired angled configuration;

[0017]FIG. 8 depicts a method embodying the invention wherein a preformed inflatable bladder in collapsed form is inserted into a length of flexible spiral metal pipe; and

[0018]FIG. 9 depicts a condition subsequent to that of FIG. 8, where the preformed bladder has been inflated.

DETAILED DESCRIPTION

[0019] The subject invention provides a lower-cost alternative to die-formed elbows and gored elbows.

[0020] As an initial step, a round section or length of spiral metal ductwork or pipe is manufactured employing a Drossbach “Spiroflex Tubeformer” Model SPF300 or similar machine. Suitable “Spiroflex Tubeformer” machines are manufactured by Drossbach GmbH & Co. KG, Max-Drossbach-Straβe 7, D-86639 Rain/Lech, Germany, and are available in the United States through Ovalformer LLC, 45 Loop Road, P.O. Box 793, Arden, N. C.28704. Flexible metal ductwork was previously known. However, previous flexible metal ductwork has been relatively light gauge (30 to 40 gauge), and cannot hold the pressures that are required in most commercial and industrial type HVAC systems. Machines such as the Drossbach SPF300 can produce flexible ductwork up to 22 gauge in thickness.

[0021] Next, the length or section of round ductwork is deformed to a flat-oval cross-section, employing an ovalizer such as is disclosed in Price et al U.S. Pat. No. 6,000,260. A suitable machine embodying the invention of Pat. No. 6,000,260 is an Ovalformer Model OF1018, manufactured by Ovalformer LLC, 45 Loop Road, P.O. Box 793, Arden, N.C. 28704.

[0022] Next, a flexible fitting machine is employed to manipulate the ovalized flexible spiral metal pipe into any one of a variety of elbows, offsets and fittings. In overview, the flexible fitting machine deforms the pipe employing a series of hydraulic actuators, and shoe and anvil sets that are custom fit to a variety of different sizes. The fitting machine can be portable to allow on-site fabrication of such fittings.

[0023] After the ductwork is deformed by the fitting machine to the required shape, flanges are mounted to its end to help the fitting maintain its shape. For example, the flanges disclosed in U.S. provisional patent application Ser. No. 60/168,498, filed Dec. 2, 1999 by Miller S. Price, Mark A. Froning and Gregory C. Moyers, titled “HVAC Flange and Flange Machine,” and in a subsequent nonprovisional application Ser. No. filed Dec. 1, 2000, the entire disclosures of which are hereby expressly incorporated by reference, may be employed to make the flanges.

[0024]FIGS. 3 and 4 illustrate elements of a fitting machine 28 embodying the invention during use.

[0025] In an exemplary embodiment, the fitting machine 28 includes a fixed table represented at 30 oriented in a X-Z plane. One end 32 of a length 34 of flexible spiral metal pipe 34, which may also be termed flexible ductwork 34, is secured to the table 30 by an end securing device represented at 33, which may take the exemplary form of an internal sleeve and an external clamp. The ductwork 34 has a free end 36 which initially extends straight up in the orientation of FIGS. 3 and 4.

[0026] A movable driven assembly, generally designated 40, includes a mounting plate 42 supporting another end of securing devices generally designated 43, which takes the form of a set of external jaws 44, as well as an internal sleeve 46, which engage the free end 36 of the ductwork 34.

[0027] A mechanism, generally designated 47, moves the end securing devices 33 and 43 relative to each other, while attached to the respective ends 32 and 36, to the end position depicted in FIGS. 3 and 4, thereby effecting bending of the length 34 of spiral metal pipe to a desired angled configuration. In FIGS. 3 and 4, a right angle bend is depicted, but any desired angle, such as 450 for example, may be made.

[0028] More particularly, driving the movable driven assembly 40 is an articulating arm mechanism 48 connected to the mounting plate 42. The arm mechanism 48 includes suitable actuators (not shown) under the control of a PLC controller, as well as feedback sensors (not shown). Preferably the articulating arm mechanism 48 has three degrees of motion.

[0029] Prior to a bending operation, at least one inner radius die 50 is rigidly mounted, and positioned at a location consistent with the inner radius of the final product. The radius die 50 is selected and positioned depending on the necessary final fitting size.

[0030] With the ductwork 34 initially in a straight up position (not illustrated) in the orientation of FIGS. 3 and 4, the arm mechanism 48 and movable driven assembly 40 are adjusted so as to position the mounting plate 42 on the free end 36 of the ductwork 34.

[0031] Under direction of the PLC controller, the arm mechanism 48 then pulls the end 36 of the ductwork 34 around the inner radius die 50.

[0032] After complete forming of the fitting, the internal and external jaws release, and the arm mechanism 48 moves back to its home position.

[0033] The fitting is then unclamped from the X-Z table 30, and the machine is ready to form the next fitting.

[0034] By omitting the step of deforming to flat-oval, a round fitting could also be made.

[0035]FIG. 5 is a side elevational view of another fitting machine 60 embodying the invention. The fitting machine 60 includes a horizontal table 62 supported on legs 64 and 66. For securing the lower end of the flexible ductwork to the table 62 there is an end securing device in the form of a set of four clamping shoes 68. The shoes 68 have threaded apertures which engage rotatable drive screws 70, so that the clamping shoes 68 selectively move towards or away from the center of the table 62 as drive motors 72 rotate the drive screws 70.

[0036] The FIG. 5 fitting machine 60 includes a movable plate 74. For securing the upper end of the ductwork to the movable plate 74 there is another end securing device in the form of a set of four clamping shoes 76 like the clamping shoes 68 on the table 62. Similarly, threaded apertures in the clamping shoes 76 engage rotatable drive screws 78 driven by drive motors 80. A fixed radius die (not shown) may be employed if required.

[0037] At the beginning of operation, the ends of a section of flexible ductwork (not shown in FIG. 5) are clamped to the table 62 and movable plate 74, with the ductwork section extending between the table 62 and movable plate 74.

[0038] The movable plate 74 has an attached arm 82 fixed to the main portion of the plate 74 and extending past a pivot point 84. The pivot point 84 is defined by a pair of pivot blocks 86 (only one of which is visible in the side elevation of FIG. 5) which move up and down within a vertical guide 88 fixed to the table 62. The pivot blocks 86 have a pair of parallel vertically-extending threaded apertures which engage a pair of rotatable drive screws 90 (only one of which is visible in the side elevation of FIG. 5) so that the pivot blocks 86 move up and down within the vertical guide 88 as drive motors 92 rotate the drive screws 90.

[0039] Pivotally attached and extending between the distal end 92 of the arm 82 and a pivot point 94 fixed with reference to the table 62 is an actuator in the form of an hydraulic cylinder 96.

[0040] The table 62, arm 82, pivot point 84 and actuator 96 accordingly comprise a mechanism, generally designated 98, for moving the end securing devices 68 and 76 relative to each other.

[0041] As the hydraulic cylinder 96 retracts and extends and as the pivot blocks 86 are driven up and down, the plate 74 with the upper end of the ductwork secured thereto, is driven through a range of motion to form the ductwork to an elbow, and then returned to a starting position after a formed elbow is unclamped and a new section of flexible ductwork is placed in position.

[0042]FIGS. 6 and 7 are plan views showing another fitting machine 100 embodying the invention. In FIG. 6, a section of flexible ductwork 102 is laid flat on a table 104 and secured by an end securing device in the form of a fixed collar 106 at one end 108. Movable collars 110 and 112 are attached to the middle 114 and opposite end 116. The movable collar 112 thus comprises another end securing device, and the movable collar 110 comprises an intermediate securing device. Two drive mechanisms 118 and 120, each movable in both the X and Y axes, are attached to the respective collars 110 and 112 (which are able to pivot). The X and Y axes drive mechanisms 118 and 120 move the collars 110 and 112 in an appropriate manner to effect bending, as shown in FIG. 7.

[0043]FIGS. 8 and 9 depict another method embodying the invention, which uses a preformed inflatable bladder 130. When fully inflated, the bladder 130 assumes the shape of an elbow. For use, the bladder 130 in collapsed form is placed inside a straight section of flexible duct 132 to be bent (FIG. 8). As the bladder 130 is inflated it assumes its final shape (FIG. 9), bending the ductwork section 132 in the process.

[0044] Accordingly, embodiments of the invention replace die-formed elbows and gored elbows with simple elbows made out of ribbed flexible duct, which simple elbows may be ovalized. The invention is embodied in methods and machines for doing the bending.

[0045] The fittings of the subject invention can be manufactured at significantly less cost compared to die-formed elbows and gored elbows, and can be custom shaped to virtually any configuration.

[0046] While specific embodiments of the invention have been illustrated and described herein, it is realized that numerous modifications and changes will occur to those skilled in the art. It is therefore to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit and scope of the invention. 

What is claimed is:
 1. A machine for making an angled ductwork fitting from a length of flexible spiral metal pipe having two ends, said machine comprising: a pair of end securing devices attachable to respective ends of the length of flexible spiral metal pipe; and a mechanism for moving said end securing devices relative to each other, while attached to the respective ends, through a range of movement to an end position which effects bending of the length of spiral metal pipe to a desired angled configuration.
 2. The machine of claim 1 , which further comprises an inner radius die positioned so as to contact a portion of the length of spiral metal pipe intermediate the two ends.
 3. The machine of claim 1 , which further comprises: an intermediate securing device attachable to a portion of the length of spiral metal pipe intermediate the two ends; and wherein said mechanism for moving the end securing devices relative to each other in addition moves the intermediate securing device relative to at least one of the end securing devices.
 4. The machine of claim 1 , wherein one of said end securing devices is attached to a fixed table, and the other of said end securing devices is attached to an articulating arm.
 5. The machine of claim 4 , which further comprises an inner radius die positioned so as to contact a portion of the length of spiral metal pipe intermediate the two ends.
 6. The machine of claim 1 , wherein said mechanism for moving said end securing devices relative to each other comprises: a table to which one of said end securing devices is attached; a movable element to which the other of said end securing devices is attached; an arm attached to said movable element and extending past a pivot point; and an actuator attached to said arm.
 7. The machine of claim 6 , wherein the position of said pivot point is adjustable.
 8. The machine of claim 1 , wherein said mechanism for moving said end securing devices relative to each other comprises an X and Y axes drive mechanism attached to one of said end securing devices.
 9. The machine of claim 8 , which further comprises: an intermediate securing device attachable to a portion of the length of spiral metal pipe intermediate the two ends; and another X and Y axes drive mechanism attached to said intermediate securing device.
 10. A method for making an angled ductwork fitting, said method comprising: providing a length of flexible spiral metal pipe having two ends; employing a machine having a pair of end securing devices attachable to respective ends of the length of flexible spiral metal pipe, and a mechanism for moving the end securing devices relative to each other, to manipulate the length of flexible spiral metal pipe to a desired configuration.
 11. The method of claim 10 , wherein said step of providing a length of flexible spiral metal pipe having two ends comprises providing a length of flat oval flexible spiral metal pipe.
 12. A method for making an angled ductwork fitting, said method comprising: providing a length of flexible spiral metal pipe having two ends; providing a preformed inflatable bladder which, when inflated, assumes the shape of an elbow; inserting the preformed inflatable bladder in a collapsed form into the length of flexible spiral metal pipe; and inflating the bladder.
 13. The method of claim 12 , wherein said step of providing a length of flexible spiral metal pipe having two ends comprises providing a length of flat oval flexible spiral metal pipe. 